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  <xsd:element name="PercentageofSalesforRoyaltiesMember" id="ptct_PercentageofSalesforRoyaltiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentandRegulatoryMilestoneMember" id="ptct_DevelopmentandRegulatoryMilestoneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Numberofdistributors" id="ptct_Numberofdistributors" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentOfMarketRate" id="ptct_PercentOfMarketRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DebtInstrumentConvertibleThresholdSalePriceOfCommonStockConversionRateProductPercentageMaximum" id="ptct_DebtInstrumentConvertibleThresholdSalePriceOfCommonStockConversionRateProductPercentageMaximum" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="EmployeeStockPurchasePlanVotingPercentageLimitPercent" id="ptct_EmployeeStockPurchasePlanVotingPercentageLimitPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MilestoneDomain" id="ptct_MilestoneDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MinimumPercentageOfDebtPrincipalAmountByInstrumentHolders" id="ptct_MinimumPercentageOfDebtPrincipalAmountByInstrumentHolders" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionDevelopmentAndRegulatoryMilestones" id="ptct_AssetAcquisitionDevelopmentAndRegulatoryMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="GrantAndCollaborationMember" id="ptct_GrantAndCollaborationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Numberofterms" id="ptct_Numberofterms" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="LiabilityDevelopmentandRegulatoryMilestoneMember" id="ptct_LiabilityDevelopmentandRegulatoryMilestoneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SalesMilestonesMember" id="ptct_SalesMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionInitialMilestone" id="ptct_AssetAcquisitionInitialMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ContingentLiabilityMilestonePotentialAchievementsProductSalesPercentage" id="ptct_ContingentLiabilityMilestonePotentialAchievementsProductSalesPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="WellcomeTrustLimitedMember" id="ptct_WellcomeTrustLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AkceaMember" id="ptct_AkceaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentMilestonePaymentObligations" id="ptct_DevelopmentMilestonePaymentObligations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedExercisePriceAsPercentageOfFairMarketValueOfCommonStock" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedExercisePriceAsPercentageOfFairMarketValueOfCommonStock" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedToStockholdersWithSpecifiedOwnershipPercentageExercisePriceAsPercentageOfFairMarketValueOfCommonStock" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedToStockholdersWithSpecifiedOwnershipPercentageExercisePriceAsPercentageOfFairMarketValueOfCommonStock" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardStockholdersSpecifiedOwnershipPercentage" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockholdersSpecifiedOwnershipPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="FinanceLeaseLiabilityToBePaidYearFourAndAfter" id="ptct_FinanceLeaseLiabilityToBePaidYearFourAndAfter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LesseeOperatingLeaseLiabilityToBePaidYearFourAndAfter" id="ptct_LesseeOperatingLeaseLiabilityToBePaidYearFourAndAfter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AssignedRoyaltyPaymentsMember" id="ptct_AssignedRoyaltyPaymentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyPurchaseAgreementMember" id="ptct_RoyaltyPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesCurrent" id="ptct_LiabilitySaleOfFutureRoyaltiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesNoncurrent" id="ptct_LiabilitySaleOfFutureRoyaltiesNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NoncashRoyaltyRevenueSaleOfFutureRoyalties" id="ptct_NoncashRoyaltyRevenueSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="NoncashInterestExpenseLiabilityRelatedToSaleOfFutureRoyalties" id="ptct_NoncashInterestExpenseLiabilityRelatedToSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ProceedsFromSaleOfFutureRoyalties" id="ptct_ProceedsFromSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentMilestoneObligationPaymentsMade" id="ptct_DevelopmentMilestoneObligationPaymentsMade" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LiabilitySaleOfFutureRoyalties" id="ptct_LiabilitySaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesRoyaltyRevenuePayable" id="ptct_LiabilitySaleOfFutureRoyaltiesRoyaltyRevenuePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesInterestExpense" id="ptct_LiabilitySaleOfFutureRoyaltiesInterestExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PaymentOfMilestoneObligation" id="ptct_PaymentOfMilestoneObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForSaleOfFutureRoyaltiesPolicyTextBlock" id="ptct_LiabilityForSaleOfFutureRoyaltiesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsTransfersBetweenLevel1Level2AndLevel3Amount" id="ptct_FairValueAssetsTransfersBetweenLevel1Level2AndLevel3Amount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseCostExcludingFinanceLeaseCosts" id="ptct_LeaseCostExcludingFinanceLeaseCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="SaleOfStockSharesAvailableToBeIssuedAndSoldValue" id="ptct_SaleOfStockSharesAvailableToBeIssuedAndSoldValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilityForSaleOfFutureRoyaltiesTableTextBlock" id="ptct_LiabilityForSaleOfFutureRoyaltiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SaleOfStockRemainingSharesAvailableForSaleAggregateOfferingValue" id="ptct_SaleOfStockRemainingSharesAvailableForSaleAggregateOfferingValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="InducementStockIncentivePlan2020Member" id="ptct_InducementStockIncentivePlan2020Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SalesRebatesCurrent" id="ptct_SalesRebatesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DebtInstrumentConversionPeriodOnOrAfterSeptember202023Member" id="ptct_DebtInstrumentConversionPeriodOnOrAfterSeptember202023Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RightsExchangeSettlementMeasurementInput" id="ptct_RightsExchangeSettlementMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="RightsExchangeSettlementPotentialMilestonesValue" id="ptct_RightsExchangeSettlementPotentialMilestonesValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AvailableForSaleDebtSecuritiesConversionPrice" id="ptct_AvailableForSaleDebtSecuritiesConversionPrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="LeaseDisclosureTextBlock" id="ptct_LeaseDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseSupplementalCashFlowDisclosureTableTextBlock" id="ptct_LeaseSupplementalCashFlowDisclosureTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FiniteLivedIntangibleAssetsAmortizationExpenseYearFourAndThereafter" id="ptct_FiniteLivedIntangibleAssetsAmortizationExpenseYearFourAndThereafter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="MilestoneObligationsRecorded" id="ptct_MilestoneObligationsRecorded" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MilestonePayable" id="ptct_MilestonePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PotentialRoyaltiesDueNetProductSales" id="ptct_PotentialRoyaltiesDueNetProductSales" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="EmployeeDirectorAndConsultantStockOptionPlan1998EquityAndLongTermIncentivePlan2009AndStockIncentivePlan2013Member" id="ptct_EmployeeDirectorAndConsultantStockOptionPlan1998EquityAndLongTermIncentivePlan2009AndStockIncentivePlan2013Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ConvertibleDebtSecurity" id="ptct_ConvertibleDebtSecurity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ClearpointEquityInvestmentsFvNi" id="ptct_ClearpointEquityInvestmentsFvNi" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ClearpointEquityInvestmentFvniUnrealizedGainLoss" id="ptct_ClearpointEquityInvestmentFvniUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="EmflazaMember" id="ptct_EmflazaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TranslarnaMember" id="ptct_TranslarnaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ResearchAndDevelopmentAndSalesMilestonesMember" id="ptct_ResearchAndDevelopmentAndSalesMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PaymentOfRoyaltyObligation" id="ptct_PaymentOfRoyaltyObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="WaylivraMember" id="ptct_WaylivraMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TegsediMember" id="ptct_TegsediMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ClearpointEquityInvestmentMember" id="ptct_ClearpointEquityInvestmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquitySecuritiesFvNiUnrealizedGainLossForeignCurrency" id="ptct_EquitySecuritiesFvNiUnrealizedGainLossForeignCurrency" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DepositsAndOtherAssetsNoncurrentMember" id="ptct_DepositsAndOtherAssetsNoncurrentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DepositsAndOtherNoncurrentAssetsMember" id="ptct_DepositsAndOtherNoncurrentAssetsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AtMarketOfferingSalesAgreementMember" id="ptct_AtMarketOfferingSalesAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NumberOfProducts" id="ptct_NumberOfProducts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FederalTaxExpenseBenefitIrcSection174ResearchAndDevelopmentExpenses" id="ptct_FederalTaxExpenseBenefitIrcSection174ResearchAndDevelopmentExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="StateTaxExpenseBenefitIrcSection174ResearchAndDevelopmentExpenses" id="ptct_StateTaxExpenseBenefitIrcSection174ResearchAndDevelopmentExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="AmendedAndRestated2013LongTermIncentivePlanMember" id="ptct_AmendedAndRestated2013LongTermIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NumberOfBuildingsLeased" id="ptct_NumberOfBuildingsLeased" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="WarrenPremisesMember" id="ptct_WarrenPremisesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LesseeOperatingLeaseBaseRentAbatement" id="ptct_LesseeOperatingLeaseBaseRentAbatement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="LesseeOperatingLeaseBaseRentAbatementPeriod" id="ptct_LesseeOperatingLeaseBaseRentAbatementPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="LesseeOperatingLeaseLiabilityToBePaidNetOfBaseRentAbatement" id="ptct_LesseeOperatingLeaseLiabilityToBePaidNetOfBaseRentAbatement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="OperatingLeaseAllowanceForLeaseImprovements" id="ptct_OperatingLeaseAllowanceForLeaseImprovements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="OperatingLeaseConstructionAccountFundingCommitment" id="ptct_OperatingLeaseConstructionAccountFundingCommitment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="OperatingLeaseLessorPaymentDueAtIssuanceOfTemporaryCertificateOfOccupancy" id="ptct_OperatingLeaseLessorPaymentDueAtIssuanceOfTemporaryCertificateOfOccupancy" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PeriodAfterWhichLetterOfCreditMayBeReducedIfLeaseNotInDefault" id="ptct_PeriodAfterWhichLetterOfCreditMayBeReducedIfLeaseNotInDefault" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="SmaFoundationMember" id="ptct_SmaFoundationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncrementalInterestExpense" id="ptct_IncrementalInterestExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RepaymentsOfConvertibleDebtIncludingAccruedInterest" id="ptct_RepaymentsOfConvertibleDebtIncludingAccruedInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="LineOfCreditCommittedLoanFacilityMember" id="ptct_LineOfCreditCommittedLoanFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LineOfCreditUncommittedLoanFacilityMember" id="ptct_LineOfCreditUncommittedLoanFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentDelayedDrawTerm" id="ptct_DebtInstrumentDelayedDrawTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="LineOfCreditCommittedDelayedDrawTermLoanFacilityMember" id="ptct_LineOfCreditCommittedDelayedDrawTermLoanFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentCovenantMinimumLiquidAssets" id="ptct_DebtInstrumentCovenantMinimumLiquidAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtInstrumentCovenantMinimumLiquidAssetsIncreasedThresholdAfterQualiedAcquisitions" id="ptct_DebtInstrumentCovenantMinimumLiquidAssetsIncreasedThresholdAfterQualiedAcquisitions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="UpstazaMember" id="ptct_UpstazaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PtcFaMember" id="ptct_PtcFaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PtcAsMember" id="ptct_PtcAsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="FiniteLivedIntangibleAssetsAdditions" id="ptct_FiniteLivedIntangibleAssetsAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="IndefiniteLivedIntangibleAssetsAccumulatedDepreciationForeignCurrencyTranslationGainLoss" id="ptct_IndefiniteLivedIntangibleAssetsAccumulatedDepreciationForeignCurrencyTranslationGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NumberOfCountriesExceedingTenPercentNetSalesThreshold" id="ptct_NumberOfCountriesExceedingTenPercentNetSalesThreshold" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="SummaryOfInterestExpenseRecognizedRelatedToDebtTableTextBlock" id="ptct_SummaryOfInterestExpenseRecognizedRelatedToDebtTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ManufacturingMember" id="ptct_ManufacturingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentLiabilityMilestonePotentialAchievementsDevelopmentalAndRegulatoryMilestones" id="ptct_ContingentLiabilityMilestonePotentialAchievementsDevelopmentalAndRegulatoryMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="CreditAgreementReserveForBorrowedFunds" id="ptct_CreditAgreementReserveForBorrowedFunds" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NumberOfMutualFundsInvestedInDenominatedInForeignCurrency" id="ptct_NumberOfMutualFundsInvestedInDenominatedInForeignCurrency" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="MilestonePayableOptionExercisedToPayInCommonStock" id="ptct_MilestonePayableOptionExercisedToPayInCommonStock" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="CommonStockConsecutiveTradingDaysWeightedAverageStockPrice" id="ptct_CommonStockConsecutiveTradingDaysWeightedAverageStockPrice" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="WeightedAverageSharePrice" id="ptct_WeightedAverageSharePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
</xsd:schema>
